Fault message: "Start of injection timing regulation" - Code 17656 in a VW Golf IV (1J5).

Our incident review department has confirmed the solution to a fault that affects the Volkswagen model - GOLF IV Variant (1J5) with 1.9 TDI engine that records a DTC of origin 17656 which tells us that there is a start of injection timing regulation fault in one of the cylinders as its regulation limit has been exceeded. This code is accompanied by various symptoms in the vehicle's engine performance. Below are detailed all the symptoms that appear:
·                     17656 - Start of injection timing regulation. Regulation incorrect. Cylinder 1, 2, 3 or 4. Regulation limits exceeded or below.

·                     Lack of engine power.

·                     Engine malfunctioning.

·                     Difficulty when starting the engine.

·                     Malfunction indicator lamp (MIL) on.

NOTE: This technical note only affects those vehicles equipped with an injection pump.

The following causes may be responsible for the aforementioned symptoms to occur:

·                     The service interval has been exceeded.

·                     There is dirt in the fuel tank and this dirt has clogged the fuel filter.

The solution that our workshop care and support department has successfully carried out is as follows:

·                     Read the fault codes in the engine control unit with the diagnostic tool.

·                     Confirm that the cited fault code is recorded that is mentioned in the symptom field of this technical note.

·                     Check that there is an optimal fuel level.

·                     Ask the customer if they have filled up with a suitable fuel.

·                     Check for leaks in the fuel supply circuit.

·                     Check for fuel impurities and quality.

·                     Replace the fuel filter.

·                     Clear the fault code recorded in the engine control unit.

It should be borne in mind that although the replacement of the fuel filter has prevented the majority of repetitions of this incident in our department, it is possible that the fault is due to another affected component, depending on the symptoms and type of vehicle. 

To be able to extract the fuel gauge correctly, the clips that secure it must be removed with great care. There are three securing clip positions for the fuel gauge which are located as shown in the image.